import java.util.ArrayList;
import java.util.List;

public class PrimeFactorization {
    public static void main(String[] args) {
        int number = 90;
        List<Integer> factors = primeFactors(number);
        System.out.print(number + "=");
        for (int i = 0; i < factors.size(); i++) {
            if (i > 0) {
                System.out.print("*");
            }
            System.out.print(factors.get(i));
        }
    }

    public static List<Integer> primeFactors(int number) {
        List<Integer> factors = new ArrayList<>();
        for (int i = 2; i <= number; i++) {
            while (number % i == 0) {
                factors.add(i);
                number /= i;
            }
        }
        return factors;
    }
}